Single crystal acoustic resonator and bulk acoustic wave filter

ABSTRACT

A method of wafer scale packaging acoustic resonator devices and an apparatus therefor. The method including providing a partially completed semiconductor substrate comprising a plurality of single crystal acoustic resonator devices provided on a silicon and carbide bearing material, each having a first electrode member, a second electrode member, and an overlying passivation material. At least one of the devices to be configured with an external connection, a repassivation material overlying the passivation material, an under metal material overlying the repassivation material. Copper pillar interconnect structures are then configured overlying the electrode members, and solder bump structures are form overlying the copper pillar interconnect structures.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a continuation-in-part application of thefollowing filed patent application, commonly owned: U.S. patentapplication Ser. No. 14/341,314, (Attorney Docket No.: A969RO-000400US)titled “WAFER SCALE PACKAGING”, filed Jul. 25, 2014. The presentapplication incorporates by reference, for all purposes, the followingfiled patent applications, all commonly owned: U.S. patent applicationSer. No. 14/298,057, (Attorney Docket No. A969RO-000100US) titled“RESONANCE CIRCUIT WITH A SINGLE CRYSTAL CAPACITOR DIELECTRIC MATERIAL”,filed Jun. 6, 2014, U.S. patent application Ser. No. 14/298,076,(Attorney Docket No. A969RO-000200US) titled “METHOD OF MANUFACTURE FORSINGLE CRYSTAL CAPACITOR DIELECTRIC FOR A RESONANCE CIRCUIT”, filed Jun.6, 2014, U.S. patent application Ser. No. 14/298,100, (Attorney DocketNo. A969RO-000300US) titled “INTEGRATED CIRCUIT CONFIGURED WITH TWO ORMORE SINGLE CRYSTAL ACOUSTIC RESONATOR DEVICES”, filed Jun. 6, 2014,U.S. patent application Ser. No. 14/449,001, (Attorney Docket No.:A969RO-000500US) titled “MOBILE COMMUNICATION DEVICE CONFIGURED WITH ASINGLE CRYSTAL PIEZO RESONATOR STRUCTURE”, filed Jul. 31, 2014, and U.S.patent application Ser. No. 14/469,503, (Attorney Docket No.:A969RO-000600US) titled “MEMBRANE SUBSTRATE STRUCTURE FOR SINGLE CRYSTALACOUSTIC RESONATOR DEVICE”, filed Aug. 26, 2014.

BACKGROUND OF THE INVENTION

The present invention relates generally to electronic devices. Moreparticularly, the present invention provides techniques related to lowdefect acoustic resonator devices and bulk acoustic wave (“BAW”) filtersand filter circuits. Merely by way of example, the invention has beenapplied to a resonator devices and BAW filters for a communicationdevice, mobile device, computing device, among others.

Mobile telecommunication devices have been successfully deployedworld-wide. Over a billion mobile devices, including cell phones andsmartphones, were manufactured in a single year and unit volumecontinues to increase year-over-year. With ramp of 4G/LTE in about 2012,and explosion of mobile data traffic, data rich content is driving thegrowth of the smartphone segment—which is expected to reach 2B per annumwithin the next few years. Coexistence of new and legacy standards andthirst for higher data rate requirements is driving RF complexity insmartphones. Unfortunately, limitations exist with conventional RFtechnology that is problematic, and may lead to drawbacks in the future.

From the above, it is seen that techniques for improving electronicdevices are highly desirable.

BRIEF SUMMARY OF THE INVENTION

According to the present invention, techniques generally related toelectronic devices are provided. More particularly, the presentinvention provides techniques related to a wafer scale packaging for aresonator device. Merely by way of example, the invention has beenapplied to a resonator device for a communication device, mobile device,computing device, among others.

In an example, the present invention provides a substrate structure andcover glass arrangement in order to achieve a low defect acousticresonator device which can singulated and electrically connected to theoutside world or other external circuitry. The substrate structure has asubstrate member comprising a lattice constant chosen to closely matchthe lattice constant of single crystal piezoelectric material resultingin high acoustic velocity in the resonator. In an example, the substratemember has an upper region, and optionally, has a plurality of recessedregions configured by the support members. The substrate has a thicknessof single crystal piezo material formed overlying the upper region. Thissubstrate can be a silicon and carbide bearing substrate member. In anexample, the thickness of single crystal piezo material has a firstsurface region and a second surface region opposite of the first surfaceregion. In an example, the structure has a plurality of exposed regionsof the second surface region of the thickness of single crystal piezomaterial, each of the exposed regions configured by at least a pair ofsupport members and is configured to form an element of the arraystructure. Of course, there can also be other features.

In an example, the present invention provides for a single crystalAl_(x)Ga_(1-x)N (0<x<1) dielectric that exhibits 30% higherpiezoelectric constant compared to a similar designed dielectricsynthesized using a thin-film sputtering deposition technique. In anexample, a sputtered AlN layer deposited using conventional thin-filmmethods has an x-ray full width half maximum (“FWHM”) measurement ofgreater than 1 degree and high dislocation density of >10¹⁰/cm². Bycomparison, a single crystal Al_(x)Ga_(1-x)N grown on silicon carbide(e.g., SiC) by CVD (e.g. MOCVD) exhibits an x-ray FWHM measurement ofless than 0.25 degree and lower dislocation density of approximately2×10¹⁰/cm². Lower defect density is expected to translate to higheracoustic velocity. Therefore, a material approach is desired to obtainhighest performance acoustic resonator for BAW filter. In one or moreexamples, the present techniques provides for growth of Al_(x)Ga_(1-x)Nlayers on silicon carbide; remove silicon carbide to form membrane;deposit electrodes on both sides of the piezoelectric layer and providecover glass approach for integrated packaging or smart glass.

In an embodiment, the present low defect density Al_(x)Ga_(1-x)N singlecrystal acoustic resonator is combined with a wafer scale packagingapparatus including a partially completed semiconductor substrate, thesemiconductor substrate comprising a plurality of single crystalacoustic resonator devices, each of the devices having a first electrodemember, a second electrode member, and an overlying metallization layerto bond with a cover glass wafer, the cover glass configured with afirst metallized surface, second metallization surface and filled viastructure available to electrically connect the two metallizationlayers; a backside via structure on the partially completedsemiconductor substrate which has patterned metal forming the secondelectrode and interconnect metal to either an adjacent resonatorelectrode or through hole via structure used to make connection from thebackside plane to the front side plane of the partially completedsemiconductor wafer; a backside cover wafer used to cover the acousticmembrane; and the resulting two electrodes being routed from the piezomembrane to the top of the cover glass.

One or more benefits are achieved over pre-existing techniques using theinvention. In particular, the invention enables a cost-effectiveresonator device for communications applications with a 30% advantage inphysical material properties. In a specific embodiment, the presentdevice can be manufactured in a relatively simple and cost effectivemanner. Depending upon the embodiment, the present apparatus and methodcan be manufactured using conventional materials and/or methodsaccording to one of ordinary skill in the art. The present device usesaluminum, gallium and nitrogen containing material that is singlecrystalline. Depending upon the embodiment, one or more of thesebenefits may be achieved. Of course, there can be other variations,modifications, and alternatives.

A further understanding of the nature and advantages of the inventionmay be realized by reference to the latter portions of the specificationand attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the present invention, reference ismade to the accompanying drawings. Understanding that these drawings arenot to be considered limitations in the scope of the invention, thepresently described embodiments and the presently understood best modeof the invention are described with additional detail through use of theaccompanying drawings in which:

FIG. 1 is a simplified diagram illustrating a surface single crystalacoustic wave resonator according to an example of the presentinvention.

FIG. 2 is a simplified diagram illustrating a bulk single crystalacoustic resonator according to an example of the present invention.

FIG. 3 is a simplified diagram illustrating a feature of a bulk singlecrystal acoustic resonator according to an example of the presentinvention.

FIG. 4 is a simplified diagram illustrating a piezo structure accordingto an example of the present invention.

FIG. 5 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention.

FIG. 6 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention.

FIG. 7 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention.

FIG. 8 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention.

FIG. 9 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention.

FIG. 10 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention.

FIG. 11 is a simplified diagram of a substrate member according to anexample of the present invention.

FIG. 12 is a simplified diagram of a substrate member according to anexample of the present invention.

FIG. 13 is a simplified table illustrating features of a conventionalfilter compared against the present examples according to examples ofthe present invention.

FIGS. 14 to 26B illustrate a manufacturing method for a single crystalacoustic resonator device according to an embodiment of the presentinvention.

FIGS. 27 to 32 illustrate a manufacturing method for wafer scalepackaging of a wafer comprising a plurality of single crystal acousticresonators devices according to an embodiment of the present invention.

FIG. 33 is a top view diagram of a bumped wafer to be singulated orprocessed according to an embodiment of the present invention.

FIGS. 34A to 34C illustrate a side-view, top-view, and bottom-viewdiagrams of a resonator device according to an embodiment of the presentinvention.

FIGS. 35 and 36 illustrate an example of mounting a resonator device ona laminate structure and a molding process according to an embodiment ofthe present invention.

FIGS. 37 to 54 illustrate a method of manufacturing a resonator deviceon a transparent substrate according to an embodiment of the presentinvention.

FIGS. 55A and 55B illustrate a plurality of resonator devices accordingto an embodiment of the present invention.

FIGS. 56A to 61D illustrate examples of resonator devices according tovarious embodiments of the present invention.

FIG. 62 is a simplified plot of insertion loss plotted against frequencyaccording to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

According to the present invention, techniques generally related toelectronic devices are provided. More particularly, the presentinvention provides techniques related to a single crystal acousticresonator. Merely by way of example, the invention has been applied to aresonator device for a communication device, mobile device, computingdevice, among others.

As additional background, the number of bands supported by smartphonesis estimated to grow by 7-fold compared to conventional techniques. As aresult, more bands mean high selectivity filter performance is becominga differentiator in the RF front end of smartphones. Unfortunately,conventional techniques have severe limitations.

That is, conventional filter technology is based upon amorphousmaterials and whose electromechanical coupling efficiency is poor (only7.5% for non-lead containing materials) leading to nearly half thetransmit power dissipated in high selectivity filters. In addition,single crystal acoustic wave devices are expected to deliverimprovements in adjacent channel rejection. Since there are twenty (20)or more filters in present smartphone and the filters are insertedbetween the power amplifier and the antenna solution, then there is anopportunity to improve the RF front end by reducing thermal dissipation,size of power amplifier while enhancing the signal quality of thesmartphone receiver and maximize the spectral efficiency within thesystem.

Utilizing single crystal acoustic wave device (herein after “BAW”device) and filter solutions, one or more of the following benefits maybe achieved: (1) large diameter silicon wafers (up to 200 mm) areexpected to realize cost-effective high performance solutions, (2)electromechanical coupling efficiency is expected to more than triplewith newly engineered strained piezo electric materials, (3) Filterinsertion loss is expected to reduce by 1dB enabling longer batterylife, improve thermal management with smaller RF footprint and improvingthe signal quality and user experience. These and other benefits can berealized by the present device and method as further provided throughoutthe present specification, and more particularly below.

FIG. 1 is a simplified diagram illustrating a surface single crystalacoustic resonator according to an example of the present invention.This diagram is merely an example, which should not unduly limit thescope of the claims. The present surface single crystal acousticresonator device 100 having a crystalline piezo material 120 overlying asubstrate 110 is illustrated. As shown, an acoustic wave propagates in alateral direction from a first spatial region to a second spatial regionsubstantially parallel to a pair of electrical ports 140, which form aninter-digital transducer configuration 130 with a plurality of metallines 131 that are spatially disposed between the pair of electricalports 140. In an example, the electrical ports on the left side can bedesignated for signal input, while the electrical ports on the rightside are designated for signal output. In an example, a pair ofelectrode regions are configured and routed to a vicinity of a planeparallel to a contact region coupled to the second electrode material.

In a SAW device example, surface acoustic waves produce resonantbehavior over a narrow frequency band near 880 MHz to 915 MHz frequencyband—which is a designated passband for a Europe, Middle East and Africa(EMEA) LTE enabled mobile smartphone. Depending on region of operationfor the communication device, there can be variations. For example, inNorth American transmit bands, the resonator can be designed such thatresonant behavior is near the 777 MHz to 787 MHz frequency passband.Other transmit bands, found in other regions, can be much higher infrequency, such as the Asian transmit band in the 2570 MHz to 2620 MHzpassband. Further, the examples provided here are for transmit bands. Insimilar fashion, the passband on the receiver side of the radio frontend also require similar performing resonant filters. Of course, therecan be variations, modifications, and alternatives.

Other characteristics of surface acoustic wave devices include thefundamental frequency of the SAW device, which is determined by thesurface propagation velocity (determined by the crystalline quality ofthe piezo-electric material selected for the resonator) divided by thewavelength (determined by the fingers in the interdigitated layout inFIG. 1). Measured propagation velocity (also referred to as SAWvelocity) in GaN of approximately 5800 m/s has been recorded, whilesimilar values are expected for AlN. Accordingly, higher SAW velocity ofsuch Group III-nitrides enables a resonator to process higher frequencysignals for a given device geometry.

Resonators made from Group III-nitrides are desirable as such materialsoperate at high power (leveraging their high critical electric field),high temperature (low intrinsic carrier concentration from their largebandgap) and high frequency (high saturated electron velocities). Suchhigh power devices (greater than 10 Watts) are utilized in wirelessinfrastructure and commercial and military radar systems to name a few.Further, stability, survivability and reliability of such devices arecritical for field deployment.

Further details of each of the elements provided in the present devicecan be found throughout the present specification and more particularbelow.

FIG. 2 is a simplified diagram illustrating a bulk single crystalacoustic resonator according to an example of the present invention.This diagram is merely an example, which should not unduly limit thescope of the claims. The present bulk single crystal acoustic resonatordevice 200 having a crystalline piezo material is illustrated. As shown,an acoustic wave propagates in a vertical direction from a first spatialregion to a second spatial region between an upper electrode material231 and a substrate member 210. As shown, the crystalline piezo material220 is configured between the upper (231) and lower (232) electrodematerial. In an embodiment, the substrate member 210 can be a siliconand carbide bearing substrate member. The top electrode material 231 isconfigured underneath a plurality of optional reflector layers, whichare formed overlying the top electrode 231 to form an acoustic reflectorregion 240.

In a bulk acoustic wave (hereinafter “BAW”) device example, acousticwaves produce resonant behavior over a narrow frequency band near 3600MHz to 3800 MHz frequency band—which is a designated passband for a LTEenabled mobile smartphone. Depending on region of operation for thecommunication device, there can be variations. For example, in North

American transmit bands, the resonator can be designed such thatresonant behavior is near the 2000 MHz to 2020 MHz frequency passband.Other transmit bands, found in other regions such as the Asian transmitband in the 2500 MHz to 2570 MHz passband. Further, the examplesprovided here are for transmit bands. In similar fashion, the passbandon the receiver side of the radio front end also require similarperforming resonant filters. Of course, there can be variations,modifications, and alternatives.

Other characteristics of single crystal BAW devices include theelectromechanical acoustic coupling in the device, which isproportionate to the piezoelectricity constant (influence by the designand strain of the single crystal piezo layer) divided by the acousticwave velocity (influenced by scattering and reflections in the piezomaterial). Acoustic wave velocity in GaN of over 5300 m/s has beenobserved. Accordingly, high acoustic wave velocity of such GroupIII-nitrides enables a resonator to process higher frequency signals fora given device geometry.

Similar to SAW devices, resonators made from Group III-nitrides aredesirable as such materials operate at high power (leveraging their highcritical electric field), high temperature (low intrinsic carrierconcentration from their large bandgap) and high frequency (highsaturated electron velocities). Such high power devices (greater than 10Watts) are utilized in wireless infrastructure and commercial andmilitary radar systems to name a few. Further, stability, survivabilityand reliability of such devices are critical for field deployment.

Further details of each of the materials provided in the present devicecan be found throughout the present specification and more particularbelow.

In an example, the device has a substrate, which has a surface region.In an example, the substrate can be a thickness of material, acomposite, or other structure. In an example, the substrate can beselected from a dielectric material, a conductive material, asemiconductor material, a carbide material, or any combination of thesematerials. In an example, the substrate can also be a polymer member, asingle crystal silicon carbide member, or the like. In a preferredexample, the substrate is selected from a material provided fromsilicon, a gallium arsenide, an aluminum oxide, or others, and theircombinations.

In an example, the substrate is silicon. The substrate has a surfaceregion, which can be in an off-set or off cut configuration. In anexample, the surface region is configured in an off-set angle rangingfrom 0.5 degree to 1.0 degree. In an example, the substrate is <111>oriented and has high resistivity (greater than 10³ ohm-cm). Of course,there can be other variations, modifications, and alternatives.

In an example, the device has a first electrode material coupled to aportion of the substrate and a single crystal capacitor dielectricmaterial having a thickness of greater than 0.4 microns (um). In anexample, the single crystal capacitor dielectric material has a suitabledislocation density. The dislocation density is less than 10¹²defects/cm², and greater than 10⁴ defects per cm², and variationsthereof. The device has a second electrode material overlying the singlecrystal capacitor dielectric material. Further details of each of thesematerials can be found throughout the present specification and moreparticularly below.

In an example, the single crystal capacitor material is a suitablesingle crystal material having desirable electrical properties. In anexample, the single crystal capacitor material is generally a galliumand nitrogen containing material such as a AlN, AlGaN, or GaN, amongInN, InGaN, BN, or other group III nitrides. In an example, the singlecrystal capacitor material is selected from at least one of a singlecrystal oxide including a high K dielectric, ZnO, MgO, or alloys ofMgZnGaInO. In an example, the high K is characterized by a defectdensity of less than 10¹² defects/cm², and greater than 10⁴ defects percm². Of course, there can be other variations, modifications, andalternatives.

In an example, the single crystal capacitor dielectric material ischaracterized by a surface region at least 50 um by 50 um, andvariations. In an example, the surface region can be 200 um×200 um or ashigh as 1000 um×1000 um. Of course, there are variations, modifications,and alternatives.

In an example, the single crystal capacitor dielectric material isconfigured in a first strain state to compensate to the substrate. Thatis, the single crystal material is in a compressed or tensile strainstate in relation to the overlying substrate material. In an example,the strained state of a GaN when deposited on silicon is tensilestrained whereas an AlN layer is compressively strain relative to thesilicon substrate.

In a preferred example, the single crystal capacitor dielectric materialis deposited overlying an exposed portion of the substrate. In anexample, the single crystal capacitor dielectric is lattice mismatchedto the crystalline structure of the substrate, and may be straincompensated using a compressively strain piezo nucleation layer such asAlN or SiN.

In an example, the device has the first electrode material is configuredvia a backside of the substrate. In an example, the first electrodematerial is configured via a backside of the substrate. Theconfiguration comprises a via structure configured within a thickness ofthe substrate.

In an example, the electrode materials can be made of a suitablematerial or materials. In an example, each of the first electrodematerial and the second electrode material is selected from a refractorymetal or other precious metals. In an example, each of the firstelectrode material and the second electrode material is selected fromone of tantalum, molybdenum, platinum, titanium, gold, aluminumtungsten, or platinum, combinations thereof, or the like.

In an example, the first electrode material and the single crystalcapacitor dielectric material comprises a first interface regionsubstantially free from an oxide bearing material. In an example, thefirst electrode material and the single crystal capacitor dielectricmaterial comprises a second interface region substantially free from anoxide bearing material. In an example, the device can include a firstcontact coupled to the first electrode material and a second contactcoupled to the second electrode material such that each of the firstcontact and the second contact are configured in a co-planararrangement.

In an example, the device has a reflector region configured to the firstelectrode material. In an example, the device also has a reflectorregion configured to the second electrode material. The reflector regionis made of alternating low impedance (e.g. dielectric) andhigh-impedance (e.g. metal) reflector layers, where each layer istargeted at one quarter-wave in thickness, although there can bevariations.

In an example, the device has a nucleation material provided between thesingle crystal capacitor dielectric material and the first electrodematerial. The nucleation material is typically AlN or SiN.

In an example, the device has a capping material provided between thesingle crystal capacitor dielectric material and the second electrodematerial. In an example, the capping material is GaN.

In an example, the single crystal capacitor dielectric materialpreferably has other properties. That is, the single crystal capacitordielectric material is characterized by a FWHM of less than one degree.

In an example, the single crystal capacitor dielectric is configured topropagate a longitudinal signal at an acoustic velocity of 5000meters/second and greater. In other embodiments where strain isengineered, the signal can be over 6000 m/s and below 12,000 m/s. Ofcourse, there can be variations, modifications, and alternatives.

The device also has desirable resonance behavior when tested using atwo-port network analyzer. The resonance behavior is characterized bytwo resonant frequencies (called series and parallel)—whereby oneexhibits an electrical impedance of infinity and the other exhibits animpedance of zero. In between such frequencies, the device behavesinductively. In an example, the device has s-parameter derived from atwo-port analysis, which can be converted to impedance. From s11parameter, the real and imaginary impedance of the device can beextracted. From s21, the transmission gain of the resonator can becalculated. Using the parallel resonance frequency along the known piezolayer thickness, the acoustic velocity can be calculated for the device.

FIG. 3 is a simplified diagram illustrating a feature of a bulk singlecrystal acoustic resonator according to an example of the presentinvention. This diagram is merely an example, which should not undulylimit the scope of the claims. As shown, diagram 300 shows the presentinvention applied as a band pass filter for RF signals. A specificfrequency range is allowed through the filter, as depicted by thedarkened block elevated from the RF spectrum underneath the wavelengthillustration. This block is matched to the signal allowed through thefilter in the illustration above. Single crystal devices can offerbetter acoustic quality versus BAW devices due to lower filter loss andrelieving the specification requirements on the power amplifier. Thesecan result benefits for devices utilizing the present invention such asextended battery, efficient spectrum use, uninterrupted callerexperience, and others.

FIG. 4 is a simplified diagram illustrating a piezo structure accordingto an example of the present invention. This diagram is merely anexample, which should not unduly limit the scope of the claims. In anexample, the structure 400 is configured on a bulk substrate member 410,including a surface region. In an example, the single crystal piezomaterial epitaxial 420 is formed using a growth process. The growthprocess can include chemical vapor deposition, molecular beam epitaxialgrowth, or other techniques overlying the surface of the substrate. Inan example, the single crystal piezo material can include single crystalgallium nitride (GaN) material, single crystal Al(x)Ga(1−x)N where0<x<1.0 (x=“Al mole fraction”) material, single crystal aluminum nitride(AlN) material, or any of the aforementioned in combination with eachother. Of course, there can also be modifications, alternatives, andvariations. Further details of the substrate can be found throughout thepresent specification, and more particularly below.

FIG. 5 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. In an example, the structure 500 is configured overlying anucleation region 430, which is overlying a surface of the substrate410. In an example, the nucleation region 430 is a layer or can bemultiple layers. The nucleation region is made using a piezo-electricmaterial in order to enable acoustic coupling in a resonator circuit. Inan example, the nucleation region is a thin piezo-electric nucleationlayer, which may range from about 0 to 100 nm in thickness, may be usedto initiate growth of single crystal piezo material 420 overlying thesurface of the substrate. In an example, the nucleation region can bemade using a thin SiN or AlN material, but can include variations. In anexample, the single crystal piezo material has a thickness that canrange from 0.2 um to 20 um, although there can be variations. In anexample, the piezo material that has a thickness of about 2 um istypical for 2 GHz acoustic resonator device. Further details of thesubstrate can be found throughout the present specification, and moreparticularly below.

FIG. 6 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. In an example, the structure 600 is configured using a GaN piezomaterial 620. In an example, each of the regions are single crystal orsubstantially single crystal.

In an example, the structure is provided using a thin AlN or SiN piezonucleation region 430, which can be a layer or layers. In an example,the region is unintentional doped (UID) and is provided to straincompensate GaN on the surface region of the substrate 410. In anexample, the nucleation region has an overlying GaN single crystal piezoregion (having Nd—Na: between 10¹⁴/cm3 and 10¹⁸/cm3), and a thicknessranging between 1.0 um and 10 um, although there can be variations.Further details of the substrate can be found throughout the presentspecification, and more particularly below.

FIG. 7 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. As shown, the structure 700 is configured using an AlN piezomaterial 720. Each of the regions is single-crystal or substantiallysingle crystal. In an example, the structure is provided using a thinAlN or SiN piezo nucleation region 430, which can be a layer or layers.In an example, the region is unintentional doped (UID) and is providedto strain compensate AlN on the surface region of the substrate 410. Inan example, the nucleation region has an overlying AlN single crystalpiezo region (having Nd—Na: between 10¹⁴/cm3 and 10¹⁸/cm3), and athickness ranging between 1.0 um and 10 um, although there can bevariations. Further details of the substrate can be found throughout thepresent specification, and more particularly below.

FIG. 8 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. As shown, the structure 800 is configured using an AlGaN piezomaterial 820. Each of the regions is single-crystal or substantiallysingle crystal. In an example, the structure is provided using a thinAlN or SiN piezo nucleation region 430, which can be a layer or layers.In an example, the region is unintentional doped (UID) and is providedto strain compensate AlN on the surface region of the substrate 410. Inan example, the AlGaN single crystal piezo layer where Al(x)Ga(1−x)N hasAl mole composition 0<x<1.0, (Nd—Na: between 10¹⁴/cm3 and 10¹⁸/cm3), athickness ranging between 1 um and 10 um, among other features. Furtherdetails of the substrate can be found throughout the presentspecification, and more particularly below.

FIG. 9 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. The structure 900 is configured using an AlN/AlGaN piezomaterial 920. Each of the regions is single-crystal or substantiallysingle crystal. In an example, the structure is provided using a thinAlN or SiN piezo nucleation region 930, which can be a layer or layers.In an example, the region is unintentional doped (UID) and is providedto strain compensate AlN on the surface region of the substrate 910. Inan example, one or more alternating stacks are formed overlying thenucleation region. In an example, the stack includes AlGaN/AlN singlecrystal piezo layer where Al(x)Ga(1−x)N has Al mole composition 0<x<1.0;(Nd—Na: between 1014/cm3 and 1018/cm3), a thickness ranging between 1.0um and 10 um; a AlN (1 nm<thickness<30 nm) serves to strain compensatelattice and allow thicker AlGaN piezo layer. In an example, the finalsingle crystal piezo layer is AlGaN. In an example, the structure has atotal stack thickness of at least 1 um and less than 10 um, amongothers. Further details of the substrate can be found throughout thepresent specification, and more particularly below.

FIG. 10 is a simplified diagram illustrating a piezo structure accordingto an alternative example of the present invention. This diagram ismerely an example, which should not unduly limit the scope of theclaims. As shown, the structure 1000 has an optional GaN piezo-electriccap layer or layers 1040. In an example, the cap layer 1040 or regioncan be configured on any of the aforementioned examples, among others.In an example, the cap region can include at least one or more benefits.Such benefits include improved electro-acoustic coupling from topsidemetal (electrode 1) into piezo material, reduced, surface oxidation,improved manufacturing, among others. In an example, the GaN cap regionhas a thickness ranging between 1 nm-10 nm, and has Nd—Na: between10¹⁴/cm3 and 10¹⁸/cm3, although there can be variations. Further detailsof the substrate can be found throughout the present specification, andmore particularly below.

FIG. 11 is a simplified diagram of a substrate member according to anexample of the present invention. This diagram is merely an example,which should not unduly limit the scope of the claims. In an example,the single crystal acoustic resonator material 1120 can be a singlecrystal piezo material epitaxial grown (using CVD or MBE technique) on asubstrate 1110. The substrate 1110 can be a bulk substrate, a composite,or other member. The bulk substrate 1110 is preferably gallium nitride(GaN), silicon carbide (SiC), silicon (Si), sapphire (Al2O3), aluminumnitride (AlN), combinations thereof, and the like.

FIG. 12 is a simplified diagram of a substrate member according to anexample of the present invention. This diagram is merely an example,which should not unduly limit the scope of the claims. In an example,the single crystal acoustic resonator material 1220 can be a singlecrystal piezo material epitaxial grown (using CVD or MBE technique) on asubstrate 1210. The substrate 1210 can be a bulk substrate, a composite,or other member. The bulk substrate 1210 is preferably gallium nitride(GaN), silicon carbide (SiC), silicon (Si), sapphire (Al2O3), aluminumnitride (AlN), combinations thereof, and the like. In an example, thesurface region of the substrate is bare and exposed crystallinematerial.

FIG. 13 is a simplified table illustrating features of a conventionalfilter compared against the present examples according to examples ofthe present invention. As shown, the specifications of the “PresentExample” versus a “Conventional” embodiment are shown with respect tothe criteria under “Filter Solution”.

In an example, the GaN, SiC and Al2O3 orientation is c-axis in order toimprove or even maximize a polarization field in the piezo-electricmaterial. In an example, the silicon substrate orientation is <111>orientation for same or similar reason. In an example, the substrate canbe off-cut or offset. While c-axis or <111> is nominal orientation, anoffcut angle between +/−1.5 degrees may be selected for one or more ofthe following reasons: (1) controllability of process; (2) maximizationof K2 of acoustic resonator, and other reasons. In an example, thesubstrate is grown on a face, such as a growth face. A Ga-face ispreferred growth surface (due to more mature process). In an example,the substrate has a substrate resistivity that is greater than 104ohm-cm, although there can be variations. In an example, the substratethickness ranges 100 um to 1 mm at the time of growth of single crystalpiezo deposition material. Of course, there can be variations,modifications, and alternatives.

As used herein, the terms “first” “second” “third” and “nth” shall beinterpreted under ordinary meaning. Such terms, alone or together, donot necessarily imply order, unless understood that way by one ofordinary skill in the art. Additionally, the terms “top” and “bottom”may not have a meaning in reference to a direction of gravity, whileshould be interpreted under ordinary meaning. These terms shall notunduly limit the scope of the claims herein.

As used herein, the term substrate is associated with Group III-nitridebased materials including GaN, InGaN, AlGaN, or other Group IIIcontaining alloys or compositions that are used as starting materials,or AlN or the like. Such starting materials include polar GaN substrates(i.e., substrate where the largest area surface is nominally an (h k l)plane wherein h=k=0, and l is non-zero), non-polar GaN substrates (i.e.,substrate material where the largest area surface is oriented at anangle ranging from about 80-100 degrees from the polar orientationdescribed above towards an (h k l) plane wherein l=0, and at least oneof h and k is non-zero) or semi-polar GaN substrates (i.e., substratematerial where the largest area surface is oriented at an angle rangingfrom about +0.1 to 80 degrees or 110-179.9 degrees from the polarorientation described above towards an (h k l) plane wherein l=0, and atleast one of h and k is non-zero.).

As shown, the present device can be enclosed in a suitable package.

FIGS. 14-26 illustrate a manufacturing method for a single crystalacoustic resonator device in an example of the present invention. Thisillustration is merely an example, and should not unduly limit the scopeof the claims herein.

Referring to these Figures, an example of a manufacturing process can bebriefly described below:

-   -   1. Start;    -   2. Provide a substrate member, e.g., 150mm or 200mm diameter        material, having a surface region;    -   3. Treat the surface region;    -   4. Form an epitaxial material comprising single crystal piezo        material overlying the surface region to a desired thickness;    -   5. Pattern the epitaxial material using a masking and etching        process to form a trench region by causing formation of an        exposed portion of the surface region through a pattern provided        in the epitaxial material;    -   6. Form topside landing pad metal, which may include a stack        that has a metal layer that reacts slowly with etchants in a        backside substrate etching process, as defined below.    -   7. Form topside electrode members, including a first electrode        member overlying a portion of the epitaxial material, and a        second electrode member overlying the topside landing pad metal;    -   8. Selectively form topside overlay metallization such as Ti/Al        (100 Å/2 um) for (a) reduce line losses and (b) provides thick        metal to attach cu-pillar, which will be later described.    -   9. Form passivation material overlying upper region of patterned        material;    -   10. Mask and remove (via etching) selective portions of the        passivation material to expose portions of the overlay topside        metallization to form bonding pads;    -   11. Mask and remove (via etching) a portion of the substrate        from the backside to form a first trench region exposing a        backside of the epitaxial material overlying the first electrode        member, and a second trench region exposing a backside of the        landing pad metal;    -   12. Optionally, remove mask from backside;    -   13. Mask and remove (via) etching portions of the backside to        expose a backside of the epitaxial material overlying the first        electrode member, and to expose a backside of the landing pad,        while causing the first trench region to include a first step        region and the second trench region to include a second step        region, while maintaining a mechanical rib structure between the        first trench region and the second trench region;    -   14. Form backside resonator metal material for the second        electrode overlying the exposed portion of the epitaxial        material (or piezo membrane) to form a connection from the        epitaxial material to the backside of the landing pad metal        coupled to the second electrode member overlying the topside        landing pad metal;    -   15. Form resonator active area using a masking and etching        process, while electrically and spatially isolating the first        electrode member from the second electrode member on the top        side, while also fine tuning the resonance capacitor; and    -   16. Perform other steps, as desired.

The aforementioned steps are provided for the formation of a resonatordevice using a single crystal capacitor dielectric. As shown, a pair ofelectrode members is configured to provide for contact from one side ofthe device. One of the electrode members uses a backside contact, whichis coupled to a metal stack layer to configure the pair of electrodes.Of course, depending upon the embodiment, steps or a step can be added,removed, combined, reordered, or replaced, or has other variations,alternatives, and modifications. Further details of the presentmanufacturing process can be found throughout the present specification,and more particularly below.

As shown in FIG. 14, the method begins by providing a substrate member1410. The substrate member has a surface region. In an example, thesubstrate member thickness is 400 um, which can have a diameter of 150mm or 200 mm diameter material, although there can be variations from 50mm to 300 mm.

In an example, the surface region of the substrate member is treated.The treatment often includes cleaning and/or conditioning. In anexample, the treatment occurs in an MOCVD or LPCVD reactor with ammoniagas flowing at high temperature (e.g. in the range from 940° C. to 1100°C.) at a pressure ranging from one-tenth of an atmosphere to oneatmosphere. In LPCVD process, dichlorosilane (DCS) is used (with orwithout the addition of Ammonia) to clean and prepare a surface forsingle crystal growth. Depending upon the embodiment, other treatmentprocesses can also be used.

In an example, the method includes formation of an epitaxial materialcomprising single crystal piezo material 1420 overlying the surfaceregion to a desired thickness, as shown. Using a configuration ofTrimethylgallium (TMG), Trimethylaluminium (TMA), ammonia (NH3) andhydrogen (H2) gases, the epitaxial material is grown under hightemperature in the range of 940° C. to 1100° C. in an atmosphericcontrolled environment using a MOCVD or LPCVD growth apparatus to athickness ranging from 0.4 um to 7.0 um, depending on target resonancefrequency of the capacitor device. The material also has a defectdensity of 10⁴ to 10¹² per cm2, although there can be variations.

In an example, the epitaxial material 1420 is patterned, as shown inFIG. 15. Patterning involves a masking and etching process. The mask isoften 1-3 um of photoresist. Etching uses chlorine-based chemistries(gases may include BC13, C12, SF6 and/or argon) in an RIE or ICP etchtool, under controlled temperature and pressure conditions to adjust theetch rate and sidewall profile. The patterning forms a trench region (orvia structure) by causing formation of an exposed portion of the surfaceregion through a pattern provided in the epitaxial material 1421.

In an example, the method forms a topside landing pad metal 1430, shownin FIG. 16, which may include a stack that has a metal layer that reactsslowly with etchants in a backside substrate etching process, as definedbelow. In an example, the metal is a refractory metal (such as tantalum,molybdenum, tungsten) or other metal (such as gold, aluminum, titaniumor platinum). The metal is used subsequently as a stop region for abackside etch process, as noted.

In an example, the method forms a topside metal structure, as shown inFIG. 17. The structure has topside electrode members, including a firstelectrode member 1441 overlying a portion of the epitaxial material, anda second electrode member 1442 overlying the topside landing pad metal1430, as shown. The metal structure can include an interconnect feedmetal 1443 and a metal interconnect 1444. The metal structure is madeusing a refractory metal (such as tantalum, molybdenum, tungsten), andhas a thickness of 300 nm, chosen such, when combined with the piezomaterial thickness, defines the resonant frequency of the capacitordevice. Furthermore, FIG. 18 shows an expanded view with bondingcontacts 1440 and overlay metal materials 1445.

The method forms a thickness of protecting material 1450, as shown inFIG. 19. In an example, the method forms a combination of silicondioxide, which forms a conforming structure, and an overlying siliconnitride capping material. The silicon dioxide and silicon nitridematerials are formed using a combination of silane, nitrogen and oxygensources and deposited using a PECVD chamber. In an example, the methodalso may include other steps or other materials, as desirable.

In an example, the method includes a mask and remove (via etching) toform contact openings. That is, selective portions of the passivationmaterial are removed to expose portions of the overlay topsidemetallization 1445 to form bonding pads. As shown, the passivationmaterial has openings for the bonding pads.

In an example, the method performs backside processing, by flipping thesubstrate top-side down. In an example, the method includes a patterningprocess of the backside of the substrate. The process uses a mask andremoval process via etching a portion of the substrate from the backsideto form a first trench region exposing a backside of the epitaxialmaterial overlying the first electrode member, and a second trenchregion exposing a backside of the landing pad metal. In an example,etching is performed using chlorine-based or fluorine-based gas ineither an RIE or ICP reactor with temperature and pressure defined tocontrol etch rate, selectivity and sidewall slope.

Referring to the FIGS. 20-23, the method performs a multiple stepbackside process. As shown, the method includes a mask 1451 and etchingprocess to remove a portion of the substrate 1411 from the backside toform a first trench region exposing a backside of the epitaxial materialoverlying the first electrode member, and a second trench regionexposing a backside of the landing pad metal. The mask is then removed.The method includes another mask 1452 and etching process, shown in FIG.23, to process portions of the backside of the substrate 1411 to exposea backside of the epitaxial material 1421 overlying the first electrode1441 member, and to expose a backside of the landing pad 1430, whilecausing the first trench region to include a first step region and thesecond trench region to include a second step region. As shown, themethod also maintains a mechanical rib structure 1413 between the firsttrench region and the second trench region.

Next in FIG. 24, the method includes formation of a backside resonatormetal material 1446 or backside electrode for the second electrode 1442overlying the exposed portion of the epitaxial material 1421 (or piezomembrane) to form a connection from the epitaxial material 1420 to thebackside of the landing pad metal 1430 coupled to the second electrodemember 1442 overlying the topside landing pad metal 1430. As shown,there can be an intentional gap 1414 between the backside electrode 1446and a portion of the substrate 2512.

As shown, the piezo membrane is sandwiched between the pair ofelectrodes 1441-1442 and 1446, which are configured from the top-sideand backside of the substrate member 1412. The member is <111> orientedsilicon substrate with a resistivity of greater than 10 ohm-cm.

In an example, the method forms or patterns the resonator active areausing a masking and etching process. The end objective is toelectrically and spatially isolate the first electrode member from thesecond electrode member on the top side, while also fine tuning theresonance capacitor. In an example, the resonator active area is 200 umby 200 um. The patterning uses chlorine-based or fluorine-based RIE orICP etching technique.

In an example, the present method can also include one or more of theseprocesses for formation of the upper electrode structures, passivationmaterial, and backside processing. In an example, the present substrateincluding overlying structures can include a surface clean using HCl:H2O(1:1) for a predetermined amount of time, followed by rinse and loadinto evaporation tool.

In the evaporation tool to form the electrode metallization, the methodincludes a molybdenum (Mo) metal (3000 Å) using an e-beam evaporationprocess technique on a masked and patterned top side of the singlecrystal piezo material. In an example, if desired, a thin titaniumadhesion metal (<100 Å) can be deposited prior to formation of the Mometal. Such titanium metal serves as a glue layer, among other features.In an example, the method performs a mask and pattern process to defineMo in field areas (leaving Mo in probe pad, coplanar waveguide (CPW)interconnect, top-plate/first electrode, via landing pad/secondelectrode, and alignment mark areas. In an example, titanium-aluminum(100 Å/4 um) is deposited on Mo metal in probe pad and CPW areas. In anexample, Ti/Al is formed on the landing pad for subsequently depositedcopper-tin metal pillars for wafer-level flip-chip package—CuSn pillarsand die sawing are deposited. In an example, the method forms adielectric passivation (25 um of spin-on polymer photo-dielectric(ELECTRA WLP SH32-1-1) of top-side surface, or alternatively acombination of SiN or SiO2 is formed overlying the top surface.

In an example, the method includes patterning to open bond pads andprobe pads by exposing photo-dielectric and developing away dielectricmaterial 1450 on pads, as shown in FIG. 25. The patterning processcompletes an upper region of the substrate structure, before backsideprocessing is performed. Further details of the present method can befound throughout the present specification, and more particularly below.

FIG. 26A shows an example of the final device 2600 with electrodeconnections 1461 and 1462 coupled to the bonding pads, and the intrinsicdevice 1401 marked by the dotted box. FIG. 26B shows device 2602, whichis a simplified representation of device 2600, with epitaxial material2621, a first electrode 2661, a second electrode 2662, andinterconnection 2604. FIG. 26B also shows equivalent circuit 2603 withthe interconnection 2604 represented within the dotted box.

In an example, the substrate is provided on a flip mount wafer and mount(using photoresist) onto a carrier wafer to begin backside process. Inan example, the backside processing uses a multi-step (e.g., two step)process. In an example, the wafer is thinned from about 500 um to about300 um and less using backside grinding process, which may also includepolishing, and cleaning. In an example, the backside is coated withmasking material, such as photoresist, and patterned to open trenchregions for the piezo material and the landing pad regions. In anexample, the method incudes a shallow etch process into the substrate,which can be silicon for example. In an example, the method coats thebackside with photoresist to open and expose a backside region of thepiezo material, which exposes a full membrane area, which includesenclosed the piezo material and the landing pad areas. In an example,the method also performs an etch until the piezo material and thelanding pads are exposed. In an example, the “rib” support is featurewhich results from 2-step process, although there can be variations, asfurther described below.

In an example, the backside is patterned with photoresist to align thebackside pad metal (electrode #2), interconnect and landing pad. In anexample, the backside is treated using a cleaning process using diluteHCl:H2O (1:1), among other suitable processes. In an example, the methodalso includes deposition of about 3000A of Mo metal in selective areas,provided that the backside of the wafer is patterned with metal in aselective manner and not blanket deposition. In an example, the metal isformed in limited areas to reduce parasitic capacitance and enablesrouting of backside for circuit implementation, which is beneficial fordifferent circuit node interconnections. In an example, if desired, athin titanium adhesion metal (<100 Å) can be deposited prior to Mo as aglue material.

In an example, the method also includes formation of a dielectricpassivation (25 um of spin-on polymer photo-dielectric (e.g., ELECTRAWLP SH32-1-1) of backside side surface for mechanical stability. In anexample in an alternative example, the method includes deposition of SiNand/or SiO2 to fill the backside trench region to provide suitableprotection, isolation, and provide other features, if desired.

In an example, the method then separates and/or unmounts the completedsubstrate for transfer into a wafer carrier. The completed substrate hasthe devices, and overlying protection materials. In an example, thesubstrate is now ready for saw and break, and other backend processessuch as wafer level packaging, or other techniques. Of course, there canbe other variations, modifications, and alternatives.

FIGS. 27-32 illustrate a manufacturing method for wafer scale packagingof a wafer comprising a plurality single crystal acoustic resonatordevices in an example of the present invention. This illustration ismerely an example, and should not unduly limit the scope of the claimsherein.

Referring to these Figures, an example of a manufacturing process can bebriefly described below:

-   -   1. Start;    -   2. Provide a partially completed semiconductor substrate, the        semiconductor substrate comprising one-or-more (N) single        crystal acoustic resonator devices, each of the N devices having        a first electrode member and a second electrode member, and an        overlying passivation material, the N devices being numbered R₁,        R₂, . . . R_(N-1), and R_(N);    -   3. For at least each of R₁ and R_(N), form a repassivation        material overlying the passivation material, the repassivation        material having a first region exposing the first electrode        member and a second region expositing the second electrode        member, such as those described in the present specification but        can include variations;    -   4. Form an under metal material overlying the repassivation        material and covering the first region and the second region        such that the first electrode member and the second electrode        member are each in electrical and physical contact with the        under metal material;    -   5. Form a thickness of resist material overlying the under metal        material to cause a substantially planarized surface region;    -   6. Pattern the substantially planarized surface region of the        thickness of resist material to expose a first region        corresponding to the first electrode member and a second region        corresponding to the second electrode member;    -   7. Fill the first region and the second region using a        deposition process to form a first copper pillar structure        overlying the first electrode member and a second copper pillar        structure overlying the second electrode member;    -   8. Form a solder material overlying the first copper pillar        structure and the second copper pillar structure;    -   9. Process the thickness of resist material to substantially        remove the thickness of resist material and expose the under        metal material;    -   10. Remove any exposed portions of the under metal material;    -   11. Subject the solder material on the first copper pillar        structure and the second copper pillar structure to cause        formation of a first solder bump structure overlying the first        copper pillar structure and a second solder bump structure        overlying the second copper pillar structure for at least each        of R₁ and R_(N).    -   12. Perform other steps, as desired.

The aforementioned steps are provided for the formation of a packagedresonator device including a single crystal capacitor dielectric. Ofcourse, depending upon the embodiment, steps or a step can be added,removed, combined, reordered, or replaced, or has other variations,alternatives, and modifications. Further details of the presentmanufacturing process can be found throughout the present specification,and more particularly below.

Referring to these Figures, the method includes providing a partiallycompleted semiconductor substrate. In an example, the semiconductorsubstrate comprises one-or-more (N) single crystal acoustic resonatordevices. Each of the N devices has a first electrode member and a secondelectrode member, and an overlying passivation material. In an example,the N devices are numbered R₁, R₂, . . . R_(N-1), and R_(N). In anexample, the partially completed semiconductor substrate can be the onedescribed in the aforementioned text.

In an example, for at least each of R₁ and R_(N), the method includesforming a repassivation material 1451 overlying the passivationmaterial, as shown in FIG. 27. In an example, the repassivation materialhas a first region exposing the first electrode member and a secondregion exposing the second electrode member, such as those described inthe present specification but can include variations.

In an example, before depositing the repassivation material, or coating,the method performs a surface cleaning process, such as oxygen (O2)plasma. Other cleaning processes include dilute acids (such as HCl:H2O)or ammonia and provide removing of oxides, polymer residue. Of course,there can be variations.

In an example, the repassivation coating 1451 is deposited usingsuitable techniques. In an example, the repassivation coating can be aBCB (Cyclotene 4024-40 material), sold by DOW Chemical or othercompanies. In an example, the coating has a thickness ranging from 1 umto 25 um and is preferably about 5 um, although there can be variations.In an example, the method also includes an align, expose, develop, andcure process. The method also includes a cleaning process, such asoxygen (O2) plasma. Of course, there can be variations.

As shown, the method includes forming an under metal material 1470overlying the re-passivation material, as shown in FIG. 28. In anexample, the under metal material 1470 can be sputter deposited orUnder-Bump-Metal (UBM) Ti—Cu (100 Å/2000 Å). In an example, the methodcovers the first region and the second region such that the firstelectrode member 1441 and the second electrode member 1442 are each inelectrical and physical contact with the under metal material 1470.

In an example, the method includes forming a thickness of resistmaterial 1471 overlying the under metal material 1470 to cause asubstantially planarized surface region, as shown in FIG. 29. In anexample, the method includes applying a negative resist mask layer 1471.In an example, the method includes developing and cleaning. That is, themethod forms a thickness of resist material ranging from 2 um to 10 um,and preferably about 5 um.

In an example, the method includes patterning the substantiallyplanarized surface region of the thickness of resist material to exposea first region corresponding to the first electrode member and a secondregion corresponding to the second electrode member. In an example, themethod includes exposing the resist material using either a UV-radiationstepper or contact aligner to expose the resist material. The resist infirst region and the second region is developed using AZ 326 MIFchemical.

In an example, the method includes filling the first region and thesecond region using a deposition process to form a first copper pillarstructure 1472 overlying the first electrode member 1441 and a secondcopper pillar structure 1472 overlying the second electrode member 1442.

In an example, the method includes forming a solder material 1473overlying the first copper pillar structure 1472 and the second copperpillar structure 1472.

In an example, the method processes the thickness of resist material1471 to substantially remove the thickness of resist material 1471 andexpose the under metal material 1451, as shown in FIG. 30.

In an example, the method removes any exposed portions of the undermetal material 1470, as shown in FIG. 31.

In an example, the method subjects the solder material on the firstcopper pillar structure 1472 and the second copper pillar structure 1472to cause formation of a first solder bump structure 1474 overlying thefirst copper pillar structure 1472 and a second solder bump structure1474 overlying the second copper pillar structure 1472 for at least eachof R₁ and R_(N). The process is shown in FIG. 32.

As shown, the copper and tin is deposited using a plating process. Thethickness ranges from 20 um to 100 um, while the target thickness ofcopper is 50 um and 20 um for tin. In an example, the bumps arecharacterized by a pitch between bumps ranging from 50 um to 500 um, andpreferably at 175 um, although there are variations.

FIG. 33 is a top view diagram of a bumped wafer 3300 to be singulated orprocessed. In an example, the method then separates and/or unmounts thecompleted substrate for transfer into a wafer or die carrier. Thecompleted substrate has the devices, and overlying protection materials.In an example, the substrate is now ready for saw and break, and otherbackend processes such as wafer level packaging, or other techniques. Ofcourse, there can be other variations, modifications, and alternatives.

In an example, the processed wafer is sawed to singulate each of thechips or each resonator/filter. In an example, the wafer is mounted onblue tape, such as Blue Adhesive Plastic Film (PVC) manufactured byNitto or Minitron. In an example, a dimension between each die is calledthe street width ranging from 20 um to 100 um and having a target is 80um. In an example, the wafer has an M×N array of devices. In an example,a saw (or laser) makes N+1 cuts along all the rows in the array, thenmakes M+1 cuts on each and all of the columns in the array. In anexample, after the cuts are complete, the blue tape is stretched onto alarge round ring to separate the devices/circuits for picking operation.Of course, there can be variations.

FIGS. 34A to 34C illustrate a side-view, top-view, and bottom viewdiagrams of the subject resonator device in an example. FIG. 34A showsthe side view 3401 of a resonator device. As shown, the device hassubstrate 3410 with an epitaxial layer 3420 formed overlying, which canbe a single crystal Group III-Nitride piezo layer. The device alsoincludes an interconnect or via structure 3431, first and secondelectrode member 3441, 3442, a backside electrode member 3443, andcopper pillar structures 3474. FIG. 34B shows the top view 3402 of thesame resonator device with six copper pillar structures 3474 configurednear an input region and an output region. FIG. 34C shows the back sideview 3403, which shows the backside electrode 3443 and the piezo layer3420. Of course, there can be other variations, modifications, andalternatives.

FIGS. 35 and 36 illustrate an example of mounting the device on alaminate structure 1480, and a molding process. These examples shows abumped single crystal acoustic resonator flip mounted onto a laminateboard 1480 with properties characterized by a thickness, dielectricconstant. Examples of such laminate materials include CX-50, MS46L and,of course, others. The laminate material has traces 1481, which canconnect between one or more planes in the laminate by a via structure1482 or the like. The traces 1481 are comprised of metal (e.g. copper)with plating material such as tin, gold, aluminum, and, of course,others. The traces 1481 on the laminate approximately 25 um thick, butcan range from 10 um to 100 um. The single crystal acoustic resonator isattached to laminate using a combination of temperature and appliedforce. As shown in FIG. 36, the single crystal acoustic resonator can beexposed or encapsulated 1490 in plastic prior to mounting on laminate.The mounted embodiment can either be a single resonator or a filtercircuit (consisting or more than one resonator).

FIGS. 37 to 54 illustrate a method of manufacturing a resonator deviceon a transparent substrate in an example. This illustration is merely anexample, and should not unduly limit the scope of the claims herein.

As shown, the method can be outlined as follows:

-   -   1. Start;    -   2. Provide a single crystal acoustic resonator device formed on        a silicon substrate having a first thickness. In an example, the        single crystal acoustic resonator device comprises a resonator        structure and a contact structure;    -   3. Form a patterned solder structure configured overlying the        single crystal acoustic resonator device and the surface region        to form a first air gap region provided from the patterned        solder structure and configured between the resonator structure        and a first portion of the mounting structure, wherein the first        air gap structure having a height of 10 microns to 50 microns,        the patterned solder structure having a patterned upper surface        region;    -   4. Form a thickness of an epoxy material overlying the patterned        upper surface region, while maintaining the resonator structure        free from any of the epoxy material;    -   5. Position a mounting substrate member to the epoxy material;    -   6. Cure the epoxy material to mate the single crystal acoustic        resonator device to the mounting substrate member. In an        example, the mounting substrate member is optically transparent,        the mounting substrate member comprising a surface region;    -   7. Process the silicon substrate to remove a portion of the        silicon substrate to form a resulting silicon substrate of a        second thickness, the second thickness being less than the first        thickness, the resulting silicon substrate having a silicon        backside region.    -   8. Perform other steps, as desired.

The aforementioned steps are provided for the formation of a packagedresonator device including a single crystal capacitor dielectric. Ofcourse, depending upon the embodiment, steps or a step can be added,removed, combined, reordered, or replaced, or has other variations,alternatives, and modifications. Further details of the presentmanufacturing process can be found throughout the present specification,and more particularly below.

Referring to FIGS. 37-40, the method includes providing a single crystalacoustic resonator device 3720 formed on a silicon substrate 3710 havinga first thickness, as shown in FIG. 37. In an example, the substrate hasa single crystal piezo material, such as GaN, AlGaN, or AlN. Thematerial has a thickness ranging from 0.4 um to 7 um, although there maybe variations. In an example, a 2 um piezo is optimal thickness for 2GHz. In an example, the substrate can be silicon, sapphire, SiC, amongothers. In an example, the piezo material is configured c-axis uporientation to achieve polarization field.

In an example, the single crystal acoustic resonator device comprises aresonator structure and a contact structure. As shown in FIG. 38, thesubstrate 3710 is a silicon substrate, an overlying single crystal piezomaterial 3720, and an electrode member or backside electrode 3746. In anexample, the electrode can be Mo, Ta or other refractory metal, typicalthickness is 300 nm, with a range of 30 nm to 4000 nm, although therecan be variations.

In an example, the method includes a mask and etch topside trench toremove piezo material 3720, as shown in FIG. 39. In an example, the etchprocess can include a reactive ion etch process using BCl3, Ar gas, SF6or others. In an example, the process uses a PlasmaTherm model 770ICP-RIE operated at 7mT, 20 sccm Cl2, 8 sccm of BCl3, 5 sccm of Ar at400 W ICP and 25 W RIE. Of course, there can be variations.

In an example, the method deposits a “Backside” plug metal 3747, asshown. The plug metal can include Ti/Al (100 Å/2 um), among others. Inan example, the metal serves as a “catch pad” for backside contact.

Referring to FIG. 41, the method forms a patterned solder materialstructure or solder dam mask 3730 configured overlying the singlecrystal acoustic resonator device and the surface region to form a firstair gap region 3719 provided from the patterned solder structure 3730and configured between the resonator structure and a first portion ofthe mounting structure or mounting substrate member, wherein the firstair gap structure or region 3719 having a height of 10 microns to 50microns. In an example, the patterned solder structure has a patternedupper surface region.

In an example, the method forms a thickness of an epoxy material 3731overlying the patterned upper surface region, while maintaining theresonator structure free from any of the epoxy material, as shown inFIG. 42.

Referring now to FIG. 43, the method positions a mounting substratemember 3739 to the epoxy material. In an example, the method cures theepoxy material 3731 to mate the single crystal acoustic resonator deviceto the mounting substrate member 3739. In an example, the mountingsubstrate member 3739 is optically transparent. In an example, themounting substrate member 3739 comprises a surface region. Further, inan example, the mounting substrate 3739 comprises of BF33 or BK7 glassmaterial, and is selected to match temperature coefficient of expansionwith the silicon substrate member.

In an example referring to FIG. 44, the method processes the siliconsubstrate to remove a portion of the silicon substrate to form aresulting silicon substrate 3711 of a second thickness, the secondthickness being less than the first thickness. In an example, theresulting silicon substrate 3711 has a silicon backside region.

In an example, the method performs a backside via and capacitor etch ofthe substrate 3712. The etch exposes a portion of the landing pad 3747and backside of piezo membrane 3721, as shown in FIG. 45. In an example,the etch can use a SF6 gas enables selective RIE process. Of course,there can be other variations, modifications, and alternatives.

Referring to FIGS. 46-48, the method forms metallization overlying thethinned substrate member, which can include a first electrode 3741 andsecond electrode 3742. In an example, the method performs a topsidecapacitor plate (with the first electrode 3741) and connect landing padto topside plane (with the second electrode 3742) deposition process. Inan example, the plate and pad are made of a suitable material such asMo, Ta or other refractory metal, among combinations thereof. In anexample, the thickness of such layer ranges from 1000 Å to 10,000 Å,while 3000Å is target thickness, although there can be variations. In anexample, the layer has a titanium (Ti) cap metal may be used to preventoxidation of refractory metal.

In an example, the method can also form via deposition a topside overlaymetal material 3745, as shown in FIG. 47. In an example, the metal has asufficient thickness for to act as a pad for probing and has lowresistance for a high quality interconnect. In an example, theinterconnect has Ti/Al (100 Å/2 um) as a target thickness, althoughthere can be thicknesses of 0.5 um to 5 um. In an example, the methodalso provides formation of a solder dam mask 3731 or other fillmaterial, which is patterned, as shown in FIG. 48. The material isconfigured to protect the surface region from scratches, and has athickness of 1 um to 50 um and a target thickness of 5 um, while therecan be variations.

Referring now to FIGS. 49-54, the method performs a bump process. In anexample, the method includes forming a repassivation material 3751overlying the solder dam mask material, as shown in FIG. 49. In anexample, the repassivation material has a first region exposing thefirst electrode member 3761 and a second region exposing the secondelectrode member 3761.

In an example, the method includes forming an under metal material 3770overlying the repassivation material and covering the first region andthe second region such that the first electrode member and the secondelectrode member are each in electrical and physical contact with theunder metal material. This is shown in FIG. 50. In an example, the metalmaterial can be a Ti/Cu seed material, among others.

In an example, the method includes forming a thickness of resistmaterial 3771 overlying the under metal material 3770 to cause asubstantially planarized surface region, as shown in FIG. 51. The resistmaterial 3771 is developed and surface cleaned.

In an example, the method includes patterning the substantiallyplanarized surface region of the thickness of resist material 3771 toexpose a first region corresponding to the first electrode member 3761and a second region corresponding to the second electrode member 3762.In an example, the method includes filling the first region and thesecond region using a deposition process to form a first copper pillarstructure 3772 overlying the first electrode member and a second copperpillar structure 3772 overlying the second electrode member.

In an example, the method includes forming a solder material 3773overlying the first copper pillar structure 3772 and the second copperpillar structure 3772. The method also processes the thickness of resistmaterial 3771 to substantially remove the thickness of resist material3771 and expose the under metal material 3770, as shown in FIG. 52.

In an example, the method also removes any exposed portions of the undermetal material 3770, as shown in FIG. 53. The method subjects the soldermaterial on the first copper pillar structure and the second copperpillar structure to cause formation of a first solder bump structure3774 overlying the first copper pillar structure and a second solderbump structure 3774 overlying the second copper pillar structure. Thisis shown in FIG. 54. Further details of various resonator devicestructures can be found throughout the present specification, and moreparticularly below.

FIGS. 55A and 55B is a plurality of resonator devices in an example ofthe present invention. FIG. 55A shows a configuration 5501 with only 1contact region containing a through via structure along with 7resonators to build a seven element filter circuit. FIG. 55B shows anequivalent block diagram 5502. Referring to FIG. 55A and 55B, thefollowing illustration configures a filter with reduced or even minimaluse of vias to save substrate area. In an example, the range of valuesfor the present filter configuration is from seven down to one, or asingle via (shown right). In an example, the present illustration usesthe following boundary conditions: (1) Input of R1 and output of R7 arearranged such they are both topside node 1; (2) maximize the number ofinternal nodes, which use common node, and (3) the common node (bottomof R2, R4, R6) combine at the top surface of the substrate. As shown,only a single via is included, which leads to savings in expense,processing, and substrate area. Of course, there are multiple examplesthat can range from the single via to seven vias or more.

In an example, the second electrodes are shared on a common internalnode using a backside connection and metallization. In an example, thefirst electrodes are shared using a top side connection, which coupleeach of them together. In an example, only R4 has a via structure, whichcouples to the lower common electrode member. Of course, there can bevariations, modifications, and alternatives. In an example, the fewervias leads to less parasitic capacitance or other loads, and reducesprocesses, and improves substrate usage, which are beneficial for themanufacture of highly integrated devices.

FIGS. 56A to 56D illustrate examples of resonator devices according toembodiments of the present invention. FIG. 56A shows a blockconfiguration 5601 of seven resonator devices configured as a7-resonator ladder BAW filter circuit. FIG. 56B shows a top view 5602 ofthe device with copper pillar bump structures 5640. In this embodiment,not every resonator is connected to a bump. Internal nodes within thefilter circuit can be internally connected and do not require connectionthrough solder bumps. FIG. 56C shows a back-side view 5603 of the samedevice and FIG. 56D shows a side view 5604 of the same device. As shown,the top view shows a pair of grounds G, G, which relate to the BAWcircuit. In an example, Sin and Sout are also shown and coupled betweenR1, R2, R3, R4, R5, R6, and R7, where R2 and R6 coupled to each other toR4 and the via. In an example, the back-side is also shown. The sideview has recessed regions and bulk regions, as shown.

FIGS. 57A shows a similar device 5701 with copper pillar bump structures5740 as shown in FIG. 56A with a cross-sectional plane marker B-B′. FIG.57B shows a cross-sectional view 5702 of the device across the B-B′plane. This device includes a substrate 5710, single crystal piezo layer5720, and copper bumps 5740.

FIGS. 58A shows a similar device 5801 with copper pillar bump structures5840 as shown in FIG. 56A with a cross-sectional plane marker C-C′. FIG.58B shows a cross-sectional view 5802 of the device across the C-C′plane. This device includes a substrate 5810, single crystal piezo layer5820, and copper bumps 5840.

FIG. 59 illustrates a flip-chip filter on laminate (multi-chip module)according to an embodiment of the present invention. As shown, thedevice 5900 can include a resonator device include a piezo layer 5920overlying a substrate 5910, which is flipped and coupled to a laminateboard 5980 through copper bumps 5940 connected to metal interconnects5981. FIG. 60 shows a similar device 6000, but the device is packaged inan encapsulation 5990.

FIGS. 61A to 61D illustrate examples of resonator devices according toembodiments of the present invention. FIG. 61A shows a blockconfiguration 6101 of seven resonator devices configured as a7-resonator ladder BAW filter circuit on laminate. Each of R1-R7 is flipchip single crystal acoustic resonators, which are selected to create adesired filter response. FIG. 61B shows a side view 6102 of the samedevice. FIG. 61C shows a top view 6103 of the same device with thecopper bumps 6140. FIG. 61D shows a backside view 6104 with the viasbeing visible and configured with Sin and Sout.

FIG. 62 is a simplified plot 6200 of insertion loss (also referred to asS21, transmission gain, or insertion gain) plotted against frequency inan example. The plot is a characteristic loss added by encapsulating thebumped resonator (or filter circuit) with plastic material. As shown,microwave s-parameter can be measured for the flip chip resonator(device or filter circuit). In an example, delta S21 is an insertionloss of the device in flip chip configuration (open air). For a goodsolution the difference between S21,p and S21,fc (defined as deltaS21)is less than the plot below. Of course, there can be other examples, andalternatives.

While the above is a full description of the specific embodiments,various modifications, alternative constructions and equivalents may beused. As an example, the packaged device can include any combination ofelements described above, as well as outside of the presentspecification. As used herein, the term “substrate” can mean the bulksubstrate or can include overlying growth structures such as a galliumand nitrogen containing epitaxial region, or functional regions,combinations, and the like. Therefore, the above description andillustrations should not be taken as limiting the scope of the presentinvention which is defined by the appended claims.

1-14. (canceled)
 15. A method of wafer scale packaging Group III-Nitridecontaining devices, the method comprising: providing a substrate memberhaving a surface region, the substrate comprising a silicon and carbidebearing material; forming a thickness of Group III-Nitride materialoverlying the surface region; forming an insulating material overlying aportion of the thickness of Group III-Nitride material; forming acontact region to expose a portion of the thickness of the GroupIII-Nitride material; forming a pillar structure comprising a coppermaterial within the contact region; and forming a thickness of soldermaterial overlying the pillar structure to cause formation of a solderbump; and bonding the solder bump to a contact member on a substratestructure.
 16. The method of claim 15 wherein the Group III-Nitridematerial is deposited by LPCVD; and further comprising usingdichlorosilane (DCS), provided with or without Ammonia, to clean andprepare a surface for single crystal growth.
 17. The method of claim 15wherein the Group III-Nitride material is selected from at least one ofa single crystal oxide including a high K dielectric, ZnO, or MgO. 18.The method of claim 15 wherein the Group III-Nitride material ischaracterized by X-ray diffraction with clear peak at a detector angle(2-θ) associated with single crystal film and whose Full Width HalfMaximum (FWHM) is measured to be less than 1.0°.
 19. A wafer scalepackage apparatus, the apparatus comprising: a mounting substratemember, the mounting substrate member being optically transparent, themounting substrate member comprising a surface region; a single crystalacoustic resonator device configured overlying the surface region, thesingle crystal acoustic resonator device comprising a resonatorstructure and a contact structure; a patterned solder structureoverlying the surface region and configured between the single crystalacoustic resonator device and the surface region; and a first air gapregion provided from the patterned solder structure and configuredbetween the resonator structure and a first portion of the mountingsubstrate member, wherein the first air gap region has a height of 10 umto 50 um; wherein the single crystal acoustic resonator device comprisesa silicon and carbide bearing substrate member, a silicon surfaceregion, and a silicon and carbide bearing backside region, an epitaxialmaterial comprising single crystal piezo material overlying the siliconand carbide bearing surface region to a desired thickness, a trenchregion to form an exposed portion of the silicon and carbide bearingsurface region through a pattern provided in the epitaxial material, atopside landing pad metal within a vicinity of the trench region andoverlying the exposed portion of the silicon and carbide bearing surfaceregion, the first electrode member overlying a portion of the epitaxialmaterial, and the second electrode member overlying the topside landingpad metal, a backside trench region exposing a backside of the epitaxialmaterial overlying the first electrode member, and exposing a backsideof the landing pad metal and a backside resonator metal materialoverlying the backside of the epitaxial material to form a connectionfrom the epitaxial material to the to the backside of the landing padmetal to couple the second electrode member overlying the topsidelanding pad metal; wherein the mounting substrate member ischaracterized by a first coefficient of thermal expansion and whereinthe silicon and carbide bearing substrate member is characterized by asecond coefficient of thermal expansion, the first coefficient ofthermal expansion being matched to the second coefficient of thermalexpansion; wherein the mounting substrate member comprises aborosilicate glass material or a boro-float glass material.
 20. A methodfor packaging a resonator device, the method using a wafer scalepackaging process, the method comprising: providing a single crystalacoustic resonator device formed on a silicon and carbide bearingsubstrate having a first thickness, the single crystal acousticresonator device comprising a resonator structure and a contactstructure; forming a patterned solder structure configured overlying thesingle crystal acoustic resonator device and the surface region to forma first air gap region provided from the patterned solder structure andconfigured between the resonator structure and a first portion of amounting substrate member, wherein the first air gap region having aheight of 10 um to 50 um, the patterned solder structure having apatterned upper surface region; forming a thickness of an epoxy materialoverlying the patterned upper surface region, while maintaining theresonator structure free from any of the epoxy material; positioning themounting substrate member to the epoxy material; curing the epoxymaterial to mate the single crystal acoustic resonator device to themounting substrate member, the mounting substrate member being opticallytransparent, the mounting substrate member comprising a surface region;and processing the silicon substrate to remove a portion of the siliconsubstrate to form a resulting silicon substrate of a second thickness,the second thickness being less than the first thickness, the resultingsilicon substrate having a silicon backside region.
 21. The method ofclaim 20 wherein the first thickness of the silicon and carbide bearingsubstrate ranges from 300 um to 1000 um and the second thickness rangesfrom 20 um to 100 um, while the silicon substrate is maintained againstthe mounting substrate member configured to act as a stiffener duringthe processing of the silicon and carbide bearing substrate, theprocessing comprising a grinding and polishing process; wherein theepoxy material is a two-stage epoxy material; wherein the height isabout 25 um; wherein the height is measured from a first perimeterregion to a second perimeter region of the first air gap.
 22. The methodof claim 20 wherein the patterned solder structure further comprises asecond air gap region provided from the patterned solder structure andconfigured between the contact structure and a second portion of themounting substrate member.
 23. The method of claim 20 wherein the singlecrystal acoustic resonator device comprises a silicon and carbidebearing substrate member, a silicon and carbide bearing surface region,and a silicon and carbide bearing backside region, an epitaxial materialcomprising single crystal piezo material overlying the silicon andcarbide bearing surface region to a desired thickness, a trench regionto form an exposed portion of the silicon and carbide bearing surfaceregion through a pattern provided in the epitaxial material, a topsidelanding pad metal within a vicinity of the trench region and overlyingthe exposed portion of the silicon and carbide bearing surface region,the first electrode member overlying a portion of the epitaxialmaterial, and the second electrode member overlying the topside landingpad metal, a backside trench region exposing a backside of the epitaxialmaterial overlying the first electrode member, and exposing a backsideof the landing pad metal and a backside resonator metal materialoverlying the backside of the epitaxial material to form a connectionfrom the epitaxial material to the backside of the landing pad metal tocouple to the second electrode member overlying the topside landing padmetal.
 24. The method of claim 20 wherein the single crystal acousticresonator device comprises a silicon and carbide bearing substratemember, a silicon and carbide bearing surface region, and a silicon andcarbide bearing backside region, an epitaxial material comprising singlecrystal piezo material overlying the silicon and carbide bearing surfaceregion to a desired thickness, a trench region to form an exposedportion of the silicon and carbide bearing surface region through apattern provided in the epitaxial material, a topside landing pad metalwithin a vicinity of the trench region and overlying the exposed portionof the silicon and carbide bearing surface region, the first electrodemember overlying a portion of the epitaxial material, and the secondelectrode member overlying the topside landing pad metal, a backsidetrench region exposing a backside of the epitaxial material overlyingthe first electrode member, and exposing a backside of the landing padmetal and a backside resonator metal material overlying the backside ofthe epitaxial material to form a connection from the epitaxial materialto the backside of the landing pad metal to couple to the secondelectrode member overlying the topside landing pad metal; and furthercomprising: forming a passivation material overlying the silicon andcarbide bearing backside region; forming a repassivation materialoverlying the passivation material, the repassivation material having afirst region exposing the first electrode member and a second regionexpositing the second electrode member; forming an under metal materialoverlying the repassivation material and covering the first region andthe second region such that the first electrode member and the secondelectrode member are each in electrical and physical contact with theunder metal material; forming a thickness of resist material overlyingthe under metal material to cause a substantially planarized surfaceregion; patterning the substantially planarized surface region of thethickness of resist material to expose a first region corresponding tothe first electrode member and a second region corresponding to thesecond electrode member; filling the first region and the second regionusing a deposition process to form a first copper pillar structureoverlying the first electrode member and a second copper pillarstructure overlying the second electrode member; forming a soldermaterial overlying the first copper pillar structure and the secondcopper pillar structure; processing the thickness of resist material tosubstantially remove the thickness of resist material and expose theunder metal material; removing any exposed portions of the under metalmaterial; and subjecting the solder material on the first copper pillarstructure and the second copper pillar structure to cause formation of afirst solder bump structure overlying the first copper pillar structureand a second solder bump structure overlying the second copper pillarstructure.
 25. The method of claim 24 wherein the single crystal piezomaterial is selected from at least one of GaN, AlN, AlGaN, InN, BN, orother group III nitrides; wherein the epitaxial material has a thicknessof greater than 0.4 um, the epitaxial material being characterized by adislocation density of less than 10¹² defects/cm².
 26. The method ofclaim 24 wherein the single crystal piezo material is selected from atleast one of GaN, AlN, AlGaN, InN, BN, or other group III nitrides;wherein the epitaxial material has a thickness of greater than 0.4 um,the epitaxial material being characterized by a dislocation density ofless than 10¹² defects/cm².
 27. The method of claim 24 wherein thesingle crystal piezo material is selected from at least one of a singlecrystal oxide including a high K dielectric, ZnO, or MgO.
 28. The methodof claim 24 wherein the single crystal piezo material is characterizedby X-ray diffraction with clear peak at a detector angle (2-θ)associated with single crystal film and whose Full Width Half Maximum(FWHM) is measured to be less than 1.0°.
 29. The method of claim 24wherein the single crystal piezo material is deposited by LPCVD; andfurther comprising using dichlorosilane (DCS), provided with or withoutammonia, to clean and prepare a surface for growth of the single crystalpiezo material.